0012 Changes in Matter: 1. identify physical, chemical, and nuclear changes in matter and examples of those changes in everyday life

• Physical change• Chemical change• Nuclear change

Physical change…

• is a change in some property of a substance.

• Usually occur during heating/cooling or when there is a change in pressure.

Chemical change

• Atoms rearrange during a chemical change, switching partners as previous connections are broken and new ones are formed.

• Evidence?

Nuclear change

• Nuclear change– Radioactive decay-

some elements have unstable nuclei, and thus emit alpha, beta or gamma radiation

• Everyday examples

– Nuclear fission• How a nuclear power

plant works

0012 Changes in Matter: 2. apply law of conservation of matter to analysis of physical and chemical changes (e.g. cutting, dissolving, forming a precipitate)

During an ordinary chemical change, there is no detectable increase or decrease in the quantity of matter.

0012 Changes in Matter: 3. recognize the characteristics of physical states of matter (e.g., temperature, density, molecular motion) animation

Some DefinitionsSome DefinitionsA solution is a A solution is a

______________________________ mixture of 2 or more mixture of 2 or more substances in a single substances in a single phase. phase.

One constituent is usually One constituent is usually regarded as the regarded as the

SOLVENTSOLVENT and the and the

others as others as SOLUTESSOLUTES..

0012 Changes in Matter: 4. identify the properties of solutions (e.g., concentration, pH, conductivity)

• SaturatedSolvent holds as much

solute as is possible at that temperature.

• UnsaturatedLess than the maximum

amount of solute for that temperature is dissolved in the solvent.

0012 Changes in Matter: 4. identify the properties of solutions (e.g., temperature).

Generally, the solubility of solid solutes in liquid solvents increases with increasing temperature.

0012 Changes in Matter: 4. identify the properties of solutions (e.g., temperature).

• The opposite is true of gases:Carbonated soft drinks

are more “bubbly” if stored in the refrigerator.

Warm lakes have less O2 dissolved in them than cool lakes.

0012 Changes in Matter: 5. analyze factors that affect rates of chemical reactions (e.g., temperature, catalysts)

• A chemical reaction involves a collision between particles.

• The particles collide and make new substances

• The particles which react are called the reactants

• The substances which are made are called the products

0012 Changes in Matter: 5. analyze factors that affect rates of chemical reactions (e.g., temperature, catalysts)

• There are four things that we can change to make the reaction go faster.

• They are

• Temperature

• Surface area

• Concentration

• Using a catalyst

Temperature

• When we increase the temperature we give the particles energy

• This makes them move faster

• This means they collide with other particles more often

• So the reaction goes faster.

Surface area

• If we make the pieces of the reactants smaller we increase the number of particles on the surface which can react.

• This makes the reaction faster.

The particles on the surface can react

When cut into smaller pieces the particles on the inside can react

Concentration

• If we make one reactant more concentrated (like making a drink of orange squash more concentrated)

• There are more particles in the same volume to react

• So the reaction goes faster.

There are less red particles in the same volume so there is less chance of a collision

There are more red particles in the same volume so there is more chance of a collision so the reaction goes faster

Using a catalyst

• A catalyst is a chemical which is added to a reaction.

• It makes the reaction go faster.

• The catalyst does not get used up in the reaction.

• It gives the reaction the energy to get started